U.S. Pat. No. 8,085,557 (“the '557 patent”) discloses a bi-directional DC-AC inverter that includes H bridge circuit, a connecting portion connected to the H bridge circuit, a smoothing filter that connects the connecting portion to the H bridge circuit, and a control section. The H bridge circuit has four switching elements. The four switching elements include two first switching elements first ends of which are connected to each other and two second switching elements second ends of which are connected to each other. The smoothing filter has a capacitor and two coils connected to the capacitor. The control section controls the first switching elements in such a manner that the two coils function as booster coils when an alternating voltage input from a system power supply is converted to a direct current voltage.